where \(P_0=3.58 \times 10^{12}\,Pa\)  and \(T_0=-6140\,K\)  in the presence of ice, while it is changed to \(P_0=4.7 \times 10^{10}\,Pa\)  and \(T_0=-4960\,K\)  in the presence of water [1]}.
In the case of mixed phases of H2O, the mass-weighted average of \(P_{vap}\)  is used [2]}:
\(\begin{split}P_{vap}(0) & = \frac{m_{ice} \, P_0 \, e^{\frac{T_0}{T}} + m_{wat}\,P_0\,e^{\frac{T_0}{T}}}{m_{ice}+m_{wat}} \\P_{vap} & = \frac{ m_{ice}^{i-1} \, P_0 \, e^{\frac{T_0}{T}} + m_{wat}^{i-1}\,P_0\,e^{\frac{T_0}{T}}}{m_{ice}^{i-1}+m_{wat}^{i-1}}\end{split}\) 
